American military officials in Iraq say U.S. troops killed three Iraqis Sunday night after coming under fire during a raid in the northern city of Mosul.

Officials say troops searching a house were attacked by suspected members of the Ansar Al Islam terrorist group.

Meanwhile, Iraqi police in Kirkuk say they have arrested four foreigners on suspicion of helping plan attacks in the area.

A police official says the two Egyptians, an Iranian and an Afghan had fake passports and are suspected of having links to militant groups responsible for attacks in the northern Iraqi oil center.

In another development, coalition officials say they have detained five men and are questioning them about Saturday's deadly suicide bombings in Karbala that killed 19 people. The officials did not identify the suspects. The dead include 12 Iraqi policemen and civilians, along with seven coalition soldiers - five Bulgarians and two from Thailand.

Insurgents used suicide bombers, mortar fire and automatic weapons in the coordinated attacks south of Baghdad that also left more than 170 people wounded, including five American soldiers and a number of other coalition troops.